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- West (U.S.) 145
- Bodies of water 108
- River engineering 108
- Northwest, Pacific 106
- Railroad engineering 50
- Canals--Design and construction--Costs 38
- United States--Appropriations and expenditures 36
- Transportation 33
- Dams--Design and construction 32
- Rivers 30
- Water resources development 29
- Locks (Hydraulic engineering) 7
- River surveys 2
- Cascade Range 1
- Railroad construction & maintenance 1
- Railroads--Design and construction 1